panic: cpu_switch: not SRUN

I've been getting these panics under moderate load,
panic: cpu_switch: not SRUN
Debugger("panic")
Stopped at Debugger+0x34: movb $0,in_Debugger.330
db> tr
Debugger(c02ba7ed) at Debugger+0x34
panic(c0292d84,c018470e,c0318fa8,c6b97b80,c0318fa8) at panic+0x8b
sw0_2(0,e,c763ed84,c016da18,e) at sw0_2
ithread_done(e) at ithread_done+0x65
ithread_handler(e,0,0,0,0) at ithread_handler+0x8c
kthread_exit() at kthread_exit
db>
This is on an MP board that is running with a UP kernel.
--
David P. Reese, Jr. daver@xxxxxxxxxxxx
http://www.gomerbud.com/daver/